Three separate lines of inquiry are underway. Following up earlier work on the dipsogenic actions of agiotensin, we have found that there is a receptor site in or adjacent to the ventral 3rd ventricle which can support angiotensin induced drinking in the absence of (or under conditions preventing access to) subfornical organ. Thus, the hypothesis that subfornical organ contains the exclusive central receptors for angiotensin's dipsogenic action is untenable. We are currently investigating whether the SFO region can support the dipsogenic response when access (of angiotensin) to the ventral 3rd ventricle region is prevented. In preliminary work, SFO response is attenuated by 65%, but it seems likely that both SFO and ventral 3rd ventricle tissue (probably OVLT) contain angiotensin receptor sites. In another series of studies it has been shown that a) the influence of circadian rhythm on ingestive behavior is heightened following lateral hypothalamic lesions (ingestion, particularly of water, occurs almost exclusively during the dark part of the cycle) and b) the attenuated response to thirst challenges typical of animals who have 'recovered' from lateral lesions is considerably eased if the challenge occurs during the dark phase. As a third line of inquiry we have demonstrated the induction of 'consummatory' responses such as eating, drinking, copulation and pup-care in rats undergoing a sustained tail-pinch. Striking parallels exist between those behaviors preferentially released during tail-pinch and the 'stimulus bound' behaviors observed during electrical stimulation of limbic and diencephalic brain sites. Tail-pinch behaviors are severely attenuated if caudate dopamine function is depressed. Also, we find a link between the neurochemical events which support tail-pinch induced behavior and those that have been related to schizophrenia and to amphetamine induced stereotypy and psychosis.